• KSBB Journal
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• 제20권5호
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• pp.371-375
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• 2005

암세포가 특정 항암제에 의해 내성을 획득하면 구조가 상이한 타 항암제에도 교차내성을 나타내는 이른바 암세포의 다약제내성(MDR)이 암 화학요법에 있어서 가장 심각한 문제가 되고 있다. 본 연구에서는 점액세균의 대사산물로부터 다약제내성 암세포에 대한 생장억제물질을 탐색하는 과정에서 cellulose 용해성 점액세균인 Sorangium cellulosum Jw1045의 대사산물에서 우수한 활성을 발견하고 그 활성본체로서 polyene-macrolide계 화합물인 chivosazole F를 분리하였다. Chivosazole F는 시험한 인체기원의 암세포에 대해 모두 강한 생장억제작용을 나타내었으며 $(IC_{50}=0.1\~10ng/ml)$, 다약제내성 암세포주인 CL02와 CP70에 대해서도 감수성세포주와 동일한 활성을 나타내었다. 이러한 사실은 chivosazole F가 암세포에 대해 다제내성을 유도하지 않는 우수한 활성물질임을 나타탬과 동시에 다제내성을 극복하는 신규 항암제 선도화합물로서의 유용성을 시사하는 것으로 그 의미가 크다.

• Journal of Microbiology and Biotechnology
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• 제26권2호
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• pp.408-420
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• 2016

This study proposes an alternative approach for the use of chitosan silver-based dressing for the control of foot infection with multidrug-resistant bacteria. Sixty-five bacterial isolates were isolated from 40 diabetic patients. Staphylococcus aureus (37%) and Pseudomonas aeruginosa (18.5%) were the predominant isolates in the ulcer samples. Ten antibiotics were in vitro tested against diabetic foot clinical bacterial isolates. The most resistant S. aureus and P. aeruginosa isolates were then selected for further study. Three chitosan sources were tested individually for chelating silver nanoparticles. Squilla chitosan silver nanoparticles (Sq. Cs-Ag⁰) showed the maximum activity against the resistant bacteria when mixed with amikacin that showed the maximum synergetic index. This, in turn, resulted in the reduction of the amikacin MIC value by 95%. For evaluation of the effectiveness of the prepared dressing using Artemia salina as the toxicity biomarker, the LC₅₀ was found to be 549.5, 18,000, and 10,000 μg/ml for amikacin, Sq. Cs-Ag⁰, and dressing matrix, respectively. Loading the formula onto chitosan hydrogel dressing showed promising antibacterial activities, with responsive healing properties for the wounds in normal rats of those diabetic rats (polymicrobial infection). It is quite interesting to note that no emergence of any side effect on either kidney or liver biomedical functions was noticed.

• Tuberculosis and Respiratory Diseases
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• 제78권2호
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• pp.78-84
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• 2015

Background: Reports of therapeutic drug monitoring (TDM) for second-line medications to treat multidrug-resistant tuberculosis (MDR-TB) remain limited. Methods: A retrospective cohort from the Virginia state tuberculosis (TB) registry, 2009-2014, was analyzed for TDM usage in MDR-TB. Drug concentrations, measured at time of estimated peak ($C_{max}$), were compared to expected ranges. Results: Of 10 patients with MDR-TB, 8 (80%) had TDM for at least one drug (maximum 6 drugs). Second-line drugs tested were cycloserine in seven patients (mean $C_{2hr}$, $16.6{\pm}10.2{\mu}g/mL$; 4 [57%] below expected range); moxifloxacin in five (mean $C_{2hr}$, $3.2{\pm}1.5{\mu}g/mL$; 1 [20%] below); capreomycin in five (mean $C_{2hr}$, $21.5{\pm}14.0{\mu}g/mL$; 3 [60%] below); para-aminosalicylic acid in five (mean $C_{6hr}$, $65.0{\pm}29.1{\mu}g/mL$; all within or above); linezolid in three (mean $C_{2hr}$, $11.4{\pm}4.1{\mu}g/mL$, 1 [33%] below); amikacin in two (mean $C_{2hr}$, $35.3{\pm}3.7{\mu}g/mL$; 1 [50%] below); ethionamide in one ($C_{2hr}$, $1.49{\mu}g/mL$, within expected). Two patients died: a 38-year-old woman with human immunodeficiency virus/acquired immune deficiency syndrome and TB meningitis without TDM, and a 76-year-old man with fluoroquinolone-resistant (pre-extensively drug-resistant) pulmonary TB and low linezolid and capreomycin concentrations. Conclusion: Individual pharmacokinetic variability was common. A more standardized approach to TDM for MDR-TB may limit over-testing and maximize therapeutic gain.

• Annals of Laboratory Medicine
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• 제38권6호
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• pp.563-568
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• 2018

Background: Delamanid, bedaquiline, and linezolid have recently been approved for the treatment of multidrug- and extensively drug-resistant (MDR and XDR, respectively) tuberculosis (TB). To use these drugs effectively, drug susceptibility tests, including rapid molecular techniques, are required for accurate diagnosis and treatment. Furthermore, mutation analyses are needed to assess the potential for resistance. We evaluated the minimum inhibitory concentrations (MICs) of these three anti-TB drugs for Korean MDR and XDR clinical strains and mutations in genes related to resistance to these drugs. Methods: MICs were determined for delamanid, bedaquiline, and linezolid using a microdilution method. The PCR products of drug resistance-related genes from 420 clinical Mycobacterium tuberculosis strains were sequenced and aligned to those of M. tuberculosis H37Rv. Results: The overall MICs for delamanid, bedaquiline, and linezolid ranged from ${\leq}0.025$ to >1.6 mg/L, ${\leq}0.0312$ to >4 mg/L, and ${\leq}0.125$ to 1 mg/L, respectively. Numerous mutations were found in drug-susceptible and -resistant strains. We did not detect specific mutations associated with resistance to bedaquiline and linezolid. However, the Gly81Ser and Gly81Asp mutations were associated with resistance to delamanid. Conclusions: We determined the MICs of three anti-TB drugs for Korean MDR and XDR strains and identified various mutations in resistance-related genes. Further studies are needed to determine the genetic mechanisms underlying resistance to these drugs.

• Tuberculosis and Respiratory Diseases
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• 제45권6호
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• pp.1143-1153
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• 1998

연구배경 : 다제내성 폐결핵 환자에서 폐절제술이 다제내성 폐결핵의 치료에 미치는 영향에 관심을 두어 폐절제술과 화학요법 즉 병합요법의 치료 효과를 화학치료 효과와 비교 분석하여 그 결과를 지표로 다제내성 폐결핵의 치료효과를 증가시키는 데 지표를 삼고자 본 연구를 시행하였다. 방 법 : 국립마산결핵병원에서 1993년 1월부터 1997년 12월까지 폐결핵 환자 중 폐절제술을 시행 받은 79예 중 INH와 RFP을 포함하는 2제 이상의 항결핵제에 내성을 가지는 다제내성폐결핵 41예를 대상으로 진료기록을 중심으로 후향적으로 조사하였다. 전체 41예의 환자는 흉부 X선 소견상 한쪽 폐야에 국한된 병변을 절제한 국소병변군과 주병변의 절제후 잔류병 변에 공동이 남은 잔류공동군과 침윤성 소견이 남은 잔류침윤군으로 나누어 각 군의 술후 균음전율, 전체치료반응율을 측정하여 Goble 등에 의한 다제내성폐결핵에 대한 화화치료의 균음전율, 전체치료반응율과 비교하였다. 균음전율의 비교는 단일분율의 분석 (analysis of single proportion)중에 이항분포(Binomial distribution)를 이용한 직접산출법(exact model)을 이용하였고, 전체치료반응율은 단일비율의 분석(analysis of single rate)중에 포아송 분포(poisson distribution)를 이용한 직접산출법(exact model)을 이용하여 p 값을 구하였고, 통계화적 의의는 p 값이 0.05 이하일 때 그 유의성을 인정하였다. 결 과 : 전체 대상 환자는 41예로 남자가 31예, 여자가 10예이었고 16세에서 60세의 연령 분포를 보였으며 중앙치가 31 세였다. 평균 2.3회의 화학치료 과거력을 가지고 있으며 술전에 평균 4.9제의 약제를 사용하였고 술전 평균 내성 약제수는 4.8제이었다. 수술은 전폐절제술이 14예, 폐엽절제술이 24예, 구역절제술이 1예, 폐업절제술과 구역절제술을 병합한 경우가 2예이었다. 단순 흉부 X-선 사진상 국소병변군이 26예, 잔류공동군이 7예, 잔류침윤군이 8예였다. 전체환자군에서 균음전율은 90.9%로 통계적으로 유의하게 높았으며 치료실패 5예와 치료종결후 추적관찰이 가능했던 21예 중 재발 2예가 나타나 전체치료반응율은 73.1%로 통계적으로 유의하게 높았다. 국소병변군의 술후 균음전율은 100%로 통계적 유의성이 있었고, 전체 치료반응율은 93.3%로 통계적으로 유의한 차이를 나타내었으며 술후 투약기간은 평균 12.2개월이었다. 국소병변군증 술후에 일차약으로 투약한 군의 전체치료반응율은 75%로 통계적으로 유의하게 좋은 결과를 보였고 술후 투약기간은 평균 7.5개월이었다. 잔류공동군의 수술에 악한 균음전율은 75%로 통계적으로 차이가 없었으며, 전체치료반응율은 14.19%로 통계적으로 유의하게 낮은 결과를 보였고 술후 투약기간은 평균 16.7개월이었다. 잔류침윤군의 술후 균음전율은 83.3%로 통계적으로 차이가 없었고, 전체치료반응율은 100%로 통계적으로 유의하게 높았고 술후 투약기간은 평균 11.8개월이었다. 결 론 : 다제내성 폐결핵의 화학치료 과정 중 적절한 시기에 수술을 시행하는 것은 그 치료결과를 상승시키는 효과가 있다. 그러나, 술후에 공동이 남을 환자들은 가능한 광범위 절제를 시행하여야 하며 모든 공동의 절제가 불가능한 경우는 수술하지 않는 것이 타당할 것으로 판단된다. 국소병변군과 잔류병변군증의 잔류침윤군의 술후 투약기간은 평균 12개월 정도로 굳이 18개월 이상의 투약이 아니라 하더라도 그 결과는 양호하며 국소병변군에서 술후 일차약제의 사용도 치료효과를 상승시키는 데 장애가 되지 않는다고 조심스럽게 말할 수 있겠다.

• Journal of Microbiology
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• 제45권6호
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• pp.590-592
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• 2007

We report the isolation of Salmonella enterica serotype Typhimurium phage type DT104 (CCARM 8104) from swine in Korea. The CCARM 8104 isolate was resistant to nalidixic acid and showed reduced susceptibility to quinolones. The CCARM 8104 isolate had a missense mutation, Asp87Asn, in the quinolone resistance-determining region in gyrA and produced PSE-1. The CCARM 8104 isolate carried two different class 1 integrons, and the PSE-1 ${\beta}$-lactamase gene was inserted into a 1,200 bp class 1 integron. The presence of DT104 with pse-1 in an integron located in a plasmid and reduced susceptibility to quinolone in swine pose a significant threat of possible horizontal spread between swine and humans.

• Journal of Microbiology and Biotechnology
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• 제30권8호
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• pp.1180-1183
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• 2020

The prevalence and characterization of plasmid-mediated quinolone resistance (PMQR) determinants in ciprofloxacin-resistant Escherichia coli isolated from a Korean commercial layer farm were studied. A total of 45 ciprofloxacin-resistant E. coli isolates were recovered and all isolates were multidrug-resistant. Eight isolates have the PMQR genes aac(6')-Ib-cr, qnrS1, and qnrB4, and seven isolates exhibited double amino acid exchange at both gyrA and parC, and have high fluoroquinolone minimum inhibitory concentrations. Five transconjugants demonstrated transferability of PMQR and β-lactamase genes and similar antimicrobial resistance. Because PMQR genes in isolates from commercial layer chickens could enter the food supply and directly affect humans, control of ciprofloxacin resistance is needed.

• 한국미생물·생명공학회지
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• 제51권4호
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• pp.555-558
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• 2023

Staphylococcus aureus is a prominent multidrug-resistant pathogen known for its resistance to a variety of antibiotics. To combat this, a wide range of antibiotics, including quinolones, is utilized. While the efficacy of quinolones against S. aureus has been established, the rise in quinolone-resistant strains, particularly in methicillin-resistant S. aureus (MRSA), has necessitated a shift in their usage patterns. Genomic sequencing plays a crucial role as it offers insights into the genetic mechanisms of resistance. Thus, we report the complete genome sequence of an oxolinic acid-resistant strain of S. aureus isolated from sweet potato leaves, a crop commonly cultivated in Korea.

• Child Health Nursing Research
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• 제22권3호
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• pp.172-181
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• 2016

Purpose: This study was conducted to examine the effect of education on infection control for multidrug resistant organism (MDRO). Methods: One group pre-post time series design was used. Infection control education for MDRO infection was provided to nurses working in the Neonatal Intensive Care Unit (NICU). Knowledge and recognition were evaluated before and after education. Hand hygiene compliance, MDRO isolation rate and central line-associated bloodstream infection (CLABSI) rate were used as outcome variables. Data from 45 nurses was used for analysis. Results: General knowledge about MDRO increased (p=.011). Responses to questions about image of MDRO and MDRO management tended to change in a positive direction (p=.046). Hand hygiene compliance was 100% at pre-test, 79.5% during education period and 98.4% at post-education period. MDRO isolation rate was 6.83 per 1,000 patient days at pre-test, 10.24 during education period and 6.68 at post-education period. CLABSI rate was 3.76 per 1,000 central line days at pre-test, 6.84 during education period and 4.71 at post-education period. Conclusion: Findings indicate that the education program is effective in improving knowledge about MDRO in NICU nurses. However, more reliable indicators should be used to determine long-term effects.

• 대한의생명과학회지
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• 제27권2호
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• pp.59-68
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• 2021

Multidrug-resistant strain of Acinetobacter baumannii (MDRAB) is an emerging pathogen in health care facilities, preventing MDRAB is a public health concern. We conducted this experiment on a clinical isolate of A. baumannii with two main goals: the role of the efflux pump system in the stress provision of carbapenem and the response to the transcription level of the efflux pump gene. A total of 34 strains of A. baumannii was isolated from the Yangsan Hospital of Pusan National University. First, when we compared and observed the expression of the efflux pump gene and antibacterial resistance to carbapenem, a strong correlation was observed between carbapenem resistance and overexpression of adeB (P=0.0056). Second, a correlation between the efflux pump and concentration gradient and tolerance to carbapenem stress at the AdeABC efflux pump genes transcription level was confirmed. Our results revealed that the expression of the AdeABC efflux pump is an important resistance determinant in obtaining antibiotic resistance of the carbapenem group in A. baumannii.